Spare us the conspiracy; atproto.at? firehose.directory? Why would google index any of those sites with no authority/age? Maybe the owners didn't submit them to give them some credibility to start. Maybe the results vary.

Google has indexed both of them, actually, you can search successfully for those two domains directly. They just don't come up when you search for "list of public atproto relays". Any other theories?

"Credibility" for Google seems to mean being around for 5 years or having over 10 million dollars. They no longer try to surface the long tail of websites.